Product Catalog Catalog Retail Products For the Home Furnace Filters View as: Display items as thumbnails Display items as a list 3M Filtrete Micro Allergen Defense Furnace Filter, 20x25x1 Inquire for pricing 3M Filtrete Micro Allergen Defense Furnace Filter, 16 x 20 x 1 Inquire for pricing NaturalAire Furnace Filter, 20" x 25" x 1" Inquire for pricing NaturalAire Furnace Filter, 20" x 20" x 1" Inquire for pricing NaturalAire Furnace Filter, 16" x 25" x 1" Inquire for pricing NaturalAire Micro Particle Furnace Filter, 16" x 20" x 1" Inquire for pricing Filtrete Micro Allergen Defense Air Furnace Filter, 16" x 25" x 1" Inquire for pricing